The present invention discloses a communication method having both defined and undefined bus communication mechanism used in an electronic that includes steps outlined below. A connection between an application program and the peripheral electronic equipment is established through a built-in driver. A proxy library and a proxy driver respectively corresponding to a user mode and a kernel mode are activated by the application program. A connection between a combination of the proxy library and the proxy driver and the peripheral electronic equipment are established by the application program. Defined commands defined by the built-in driver are transmitted to and received from the peripheral electronic equipment through a bus by the application program by using the built-in driver. Non-defined commands not defined by the built-in driver are transmitted to and received from the peripheral electronic equipment through the bus by the application program by using the proxy library and the proxy driver.